NAGOYA, Oct 10 (Reuters) - Boeing Co is on course to achieve a difficult production target for its fuel-efficient 787 Dreamliner jets, an executive said on Wednesday, after the company fell behind its initial delivery schedule due to development delays.

"We made mistakes along the way. We are currently on path to achieve 10" a month, Jeffrey Luckey, vice president in charge supply management for the 787, said on the sidelines of the Japan Aerospace International Exhibition in Nagoya.

Boeing now makes three and a half of the new carbon-composite jets a month. It plans to raise output to five a month by the end of the year and then to 10 a month by the end of 2013. The company now has 325 suppliers building parts for the 787 in 5,000 factories worldwide, Luckey said.

Japanese companies including Fuji Heavy Industries Ltd

and Mitsubishi Heavy Industries Ltd are building the wings and other sections of Boeing's latest passenger jet equal to more than a third of the plane. It is the first time the U.S. company has asked foreign firms to build the wings for one of its jets.

Final assembly of the Dreamliner is done in the United States at Boeing plants in South Carolina and Washington. Japan's All Nippon Airways was the launch customer for the 787, having so far ordered 66 jets, which it has put at the center of its fleet planning.

Boeing's new, lightweight, fuel-efficient passenger jet was plagued by supply chain problems and production delays. So far Boeing has won 824 orders for the plane and has delivered around 60.